Doepfer

Hello. I've noticed that my A-110 VCO can't get octave jumps when I change Range positions. 

Before that I was using a keyboard connected to a A-190-2 and noticed that it was not making a regular tonal scale. So I tried to adjust the A-110 to make an exact octave jump when I turned range knob. I read the A-110 service manual and tried adjusting the potentiometer P5 and P7 to get the Range positions make octave jumps. 

I tuned the sound coming from the A110 to a C1 from the keyboard turning potentiometer P6. With Range set at 0 I got C1. But turning Range to +1 I got a B flat, and at Range +2 I got A, and at Range -1 I got C sharp. I keep trying tried to adjust P7 and P5 potentiometers but could still not get octave jumps. Does it have relation to temperature adjust? Any help? 

Thanks,

Sidney

Hello,

Didn't you make adjustments at the A-190-2? First you must be 150% sure 
that the A-190-2 is trimmed correctly. For adjusting The A-190-2 you 
definitely will be in need of a 4digit voltmeter. Do not touch the VCO 
until you did not adjust the A-190-2


Florian

Hi Florian. I did try to adjust the VCO disconnected from the A-190-2, by trying to make octave jumps from Range 0 to +1, +2 and -1. I've adjusted potentiometer P6 that the VCO Range 0 would sound the same note as a C1 from my keyboard. I've tried to make the octave jumps turning the P7 and P5 potentiometers. It's like I have a shorter scale, since I have a C note at Range 0 and a B note at Range +1. 

Altough I'm noting right now that a chart from the "VCO-Offset and Range adjustement procedures" at service manual tells that C2 would give me a lower octave and so on. Wouldn't it give a higher octave?

Sidney

--- In Doepfer_a100@yahoogroups.com, Florian Anwander <fanwander@...> wrote:

>
> Hello,
> 
> Didn't you make adjustments at the A-190-2? First you must be 150% sure 
> that the A-190-2 is trimmed correctly. For adjusting The A-190-2 you 
> definitely will be in need of a 4digit voltmeter. Do not touch the VCO 
> until you did not adjust the A-190-2
> 
> 
> Florian
>

> Hi Florian. I did try to adjust the VCO disconnected from the
> A-190-2, by trying to make octave jumps from Range 0 to +1, +2
> and -1. I've adjusted potentiometer P6 that the VCO Range 0 would
> sound the same note as a C1 from my keyboard. I've tried to make
> the octave jumps turning the P7 and P5 potentiometers. It's like
> I have a shorter scale, since I have a C note at Range 0 and a B
> note at Range +1.
>
> Altough I'm noting right now that a chart from the "VCO-Offset
> and Range adjustement procedures" at service manual tells that C2
> would give me a lower octave and so on. Wouldn't it give a higher octave?
>
> Sidney

To adjust the A-110 you need a precise 1V/Oct control voltage , e.g. an
exactly to 1.00V/oct adjusted Midi-to-CV interface like A-190-1 or A-190-2.
Otherwise you will not be able to adjust the A-110 in the right way. Rather
you may destroy the possibly correct adjustment of the A-110 ! You have to
follow the instructions given in the service manual and pay attention to the
adjustment sequence as described in the service manual. If you do not keep
the order mentioned in the service manual you will not succeed !

Best wishes
Dieter Doepfer

Hello Doepfer. I thought that I could tune without a midi module. 

Thank you,

Sidney

--- In Doepfer_a100@yahoogroups.com, <yahoo@...> wrote:

>
> > Hi Florian. I did try to adjust the VCO disconnected from the
> > A-190-2, by trying to make octave jumps from Range 0 to +1, +2
> > and -1. I've adjusted potentiometer P6 that the VCO Range 0 would
> > sound the same note as a C1 from my keyboard. I've tried to make
> > the octave jumps turning the P7 and P5 potentiometers. It's like
> > I have a shorter scale, since I have a C note at Range 0 and a B
> > note at Range +1.
> >
> > Altough I'm noting right now that a chart from the "VCO-Offset
> > and Range adjustement procedures" at service manual tells that C2
> > would give me a lower octave and so on. Wouldn't it give a higher octave?
> >
> > Sidney
> 
> To adjust the A-110 you need a precise 1V/Oct control voltage , e.g. an
> exactly to 1.00V/oct adjusted Midi-to-CV interface like A-190-1 or A-190-2.
> Otherwise you will not be able to adjust the A-110 in the right way. Rather
> you may destroy the possibly correct adjustment of the A-110 ! You have to
> follow the instructions given in the service manual and pay attention to the
> adjustment sequence as described in the service manual. If you do not keep
> the order mentioned in the service manual you will not succeed !
> 
> Best wishes
> Dieter Doepfer
>

> Hello Doepfer. I thought that I could tune without a midi module.
>
> Thank you,
>
> Sidney

A midi module is not essential but you need any CV source that generates
exact 1.00V steps to adjust the VCO scale. Another possibility would be a
CV/Gate keyboard or an A-176 with a precise multimeter (with the three
outputs adjusted e.g. to 1.00V, 2.00V and 5.00). In any case you have to
make sure that the CV source deliveres exact 1.00 intervals.

Best wishes
Dieter Doepfer